Fish like electric eels and torpedoes have specially designed nerve cells that allow them to discharge hundreds of volts of electricity.

Now, while pure water is usually nonconductive, the dissolved salts and other stuff in both sea and fresh water allow them to be conductive. If an electric fish is able to use its electricity to stun enemies or prey, how come the fish itself is unaffected?

@TheMachineCharmer But a snake would get hurt if bit by itself (or by another of the same species), as long as the venom can act on its tissues.
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Mark CNov 8 '10 at 7:13

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@Machine: Mark is correct. Snakes do not necessarily have immunity to their own venom; they are merely careful enough not to bite themselves. Their cells are as susceptible to venom proteins as the cells of any other animal.
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user172Nov 8 '10 at 7:18

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Agreed he is right and you too! The comment wasn't supposed to be taken seriously. :)
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Pratik DeoghareNov 8 '10 at 9:44

@TheM Yes, but I just had to point it out.
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Mark CNov 10 '10 at 17:51

Are we supposed to understand that the small fish has a lower resistance because it is smaller i.e. it contains less resistive material? And what about the resistance of water?
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Alexandre JasminNov 2 '13 at 0:57

@AlexandreJasmin Actually the predator fish can increase his own resistance, see Mark C's answer.
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user144542Aug 15 '14 at 17:29

I'd love to join the upvoters, but I have to point out instead that this doesn't actually answer the question. The question can be translated to "why does the eel have higher resistance". This answer assumes we know the answer to that!
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GreenAsJadeSep 30 '14 at 8:20

The simple answer is that electric eels insulate their critical tissues with a layer of fat below the skin, preventing the shock from traveling through their body as the "path of least resistance". I may update with visuals and details if I can find good ones.